Directionally adjustable fans have long been known. Such fans are useful when it is desirable to direct the airflow from the fan in a specific direction without moving the base of the fan.
Directionally adjustable fans that are capable of pivoting about both the vertical axis and the horizontal axis are typically designed with two pivot mechanisms—one for each axis. One type of pivot mechanism which allows adjustment of the vertical direction of the airflow includes coupling the fan assembly to rotatable mounts at each of the two ends of the diameter of the fan assembly forming an axis of rotation that is parallel to the floor of the base of the fan. Alternatively, the fan assembly is coupled to an arm which is rotatably mounted to the base, thereby allowing the fan to rotate about the horizontal axis defined by the rotatable mount. The horizontal direction of the airflow is adjusted by coupling the fan to the base through a mounting that is rotatable about the vertical axis. According to either design, adjusting the direction of airflow from the fan in both the vertical and horizontal axis requires the separate adjustment of two rotatable mountings.
Once the fan is adjusted so that the airflow generated flows in the desired direction, a mechanism is typically employed to preserve the adjustments in the event an external force is applied to the fan that would alter the position of the fan. Typically, the angular adjustments made to the fan are maintained by friction within the rotatable mount. Another way of preserving the angular adjustments is by tightening a screw coupled to each rotatable mount to increase the friction. Additionally, the screw could be loosened to allow adjustments to be made more easily. These frictional forces may be further increased by employing a gear structure of radially extending teeth between the mounting contact surfaces. However, the gear teeth decrease the precision of the adjustments since the teeth must properly mesh at predefined positions. Also, the gears increase the difficulty in making the adjustments since the mount surfaces no longer smoothly glide as the mounting is rotated.
Similar mounting devices have been provided for other appliances in addition to fans. Space heaters have been rotatably mounted to allow for adjusting the direction of the heat. Mirrors are frequently attached to a table stand and provide two or more rotatable mountings so that the mirror can be adjusted about the vertical and horizontal axis. Rotatable mirror mountings can also be fixed to a wall by an extendable arm, thereby allowing the mirror to be pulled away from the wall and rotatably adjusted.